Alternating Current

AC voltage varies sinusoidally as v

AC voltage varies sinusoidally as v = vm sin ωt, where vm is peak voltage and ω is angular frequency. This drives an alternating current that also var

When AC voltage is applied

When AC voltage is applied to a pure resistor, current and voltage are in phase (φ = 0). The current follows Ohm's law: i = vm sin ωt / R. Average pow

In a pure inductor

In a pure inductor, current lags voltage by π/2 (90°). The opposition to current flow is inductive reactance XL = ωL. Current amplitude: im = vm/XL. A

In a pure capacitor

In a pure capacitor, current leads voltage by π/2 (90°). The opposition is capacitive reactance XC = 1/ωC. Current amplitude: im = vm/XC. No net energ

Phasors are rotating vectors that represent

Phasors are rotating vectors that represent AC quantities. They rotate with angular frequency ω, and their vertical projections give instantaneous val